A passenger service unit as known in the state of the art are widely used in civil aircraft comprising for instance a reading light, a passenger or crew air or oxygen supply device, oxygen masks, warning lights and the like appliances. In particular an oxygen supply unit usually is part of an oxygen supply device wherein the unit is stored in a container of the aforementioned kind. In some aircrafts one passenger service unit is provided for each seat of a passenger and crew member. In other aircrafts one single passenger service unit is provided for a number of the seats, for instance in a particular for a row of seats. A row usually is aligned crosswise to an alley of seats.
Containers of oxygen supply units of the aforementioned kind usually are arranged adjacent to each other, side by side, to allow an arrangement of a number of oxygen supply devices in a ceiling-panel along an aircrafts cabin, in particular along an aircrafts cabin alley of seats. Such oxygen supply devices are referred to as OBOGS (on-board-oxygen-generating-systems) and are adapted to temporarily or continuously provide oxygen to a passenger or crew member of an aircraft. Various methods of generating oxygen are known; basically one is adapted for physically generating oxygen gas by means of an oxygen pressure cylinder and another one is adapted for chemically generating oxygen by means of a chemical oxygen generator. Thereby a certain amount of air or continuous air flow comprising a sufficient or high concentration of oxygen can be provided to a passenger or crew member.
In an emergency situation, such emergency oxygen devices in a system of an arrangement of a number of such devices are used to supply oxygen to passengers or crew members of an aircraft; in particular, emergency situations can result from a decompression situations or smoke or the like on board of the aircraft. Usually, the oxygen masks are stored above the passenger in a ceiling compartment, usually in a separate casing, like for instance the above mentioned container. In case of an emergency situation, it is to be guaranteed with sufficient reliability that oxygen masks can be released and fall out of the container. Thus, upon a door opening, the oxygen masks then are provided to the passenger at a certain level defined by means to connect the oxygen masks in the dropped state relative to the container, the oxygen generator or any other fixed point above the passenger.
Therefore, it is highly desirable to know about the status of the containers to guarantee in advance that the container will work as demanded in an emergency situation. In particular, the functioning of the container's door, in particular relative to the containers well is of particular interest. The reason is that, in an above mentioned arrangement of containers to form a passenger supply unit in an above mentioned system of an arrangement of a number of oxygen supply devices in a ceiling panel, unavoidable stress or external forces are exerted to the container. Nevertheless, it is to be prevented that stress or forces work detrimental to the functioning of the container for releasing the oxygen masks.
In particular, it is highly desirable to provide a tool for in advance knowing the status of the container with regard to the question whether the container is ready for functioning or not.